<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const p = new Promise(function (resolve,reject) {
            setTimeout(function () {
                let data = 'success';
                let data2 = 'fail'
                resolve(data);
                reject(data2)
            },1000)
        })
        console.log('同步消息');

        p.then(
        //     function (value) {
        //     console.log(value);
        // }
        ).catch(function(value) {//接收错误的
            console.error(value);
        })
    </script>
</body>
</html>